A film packet for daylight handling of photosensitive film and a cooperating film holder are disclosed in U.S. Pat. Nos. 4,821,054 and 4,821,055. The packet has film removably attached to a carrier. At one end the carrier has an asymmetrical tab bearing adhesive material, and at its opposite end has a transverse light-locking element. Telescopically receivable over the carrier and film is a light-shielding envelope. The envelope has an open end that is closeable by engagement with a light-locking element, and has a closed end with a sealing area that overlies and, when grasped, adheres to the tab to prevent inadvertent separation of the envelope from the carrier. An adjacent area not overlying the tab is graspable for pulling the sealing area free of the tab and for pulling the envelope away from the film to permit intended exposure. The packet is slidably insertable into and withdrawable from the cooperating holder which includes a spring-loaded pressure-applying member for maintaining the film in an exposure plane and a spring-loaded latching member engageable with the light-locking element to retain the carrier in place. U.S. Pat. Nos. 4,616,914; 4,413,896; 4,181,418; 4,126,465; 3,953,870; 3,899,337; 2,628,545 and 1,158,902 disclose other film holders, film packets and light locks.
In a film holder such as is disclosed in U.S. Pat. No. 4,821,055 for use with film packets of the type disclosed in U.S. Pat. No. 4,821,054, there is a difficulty in providing adequate light protection for the sensitized photographic film in the packet during the time that the covering envelope is withdrawn for exposure of the film. The opening in the end of the holder must be sufficiently wide to allow the metallic clip at the end of the film carrier to pass freely into and out of the holder for loading and unloading while maintaining adequate contact between the light lock material surfaces and the film packet envelope to prevent light from entering the holder during the film exposure portion of the usage cycle. The holder provides a mildly serpentine path for the clip to travel over the first light lock strip, then under the second light lock strip, by separating the two light lock strips in the direction of clip travel.
Ideally, the stiffness of the envelope results in adequate contact between opposite exterior surfaces of the envelope and the corresponding light lock strip to prevent light from entering the holder. Unfortunately, the mildly serpentine path does not allow for distortion or displacement of the envelope by the user as the user attempts to withdraw the envelope to the `expose` position and as the user returns it to the closed position after film exposure. Accordingly, it will be appreciated that it would be highly desirable to have a film packet and film holder which allow for the distortion and displacement of the envelope by the user during normal operation.